Current government regulations require placarding of flammable and otherwise hazardous materials during transportation. For tankers and storage tanks transported inside of a service truck, placards are typically required at each side and each end of the vehicle. Examples of such placarding can be found in U.S. Pat. No.: 4,106,229, issued Aug. 15, 1978 to H. F. Schmid; U.S. Pat. No. 4,094,083, issued Jun. 13, 1978 to H. Fund; U.S. Pat. No. 3,510,975, issued May 12, 1970 to W. J. Lowmaster, and U.S. Pat. No. 3,958,350, issued May 25, 1976 to J. Garson. Each of these patents is directed to a generally permanent sign assembly that is bolted or otherwise similarly attached to the vehicle.
For storage tanks transported on a tank setting or other flat-bed trailer, the tank itself must typically be placarded at each side and each end of the tank. For these storage tanks, the placarding requirements may only be temporary; that is, during transportation of the tanks. In these instances, the permanent signage disclosed in the above-noted patents may not be desirable. Various arrangements have been proposed for temporary placarding of vehicles themselves. See, for example, U.S. Pat. No.: 5,955,464, issued Oct. 26, 1993 to R. L. Marecek; U.S. Pat. No. 3,701,210, issued Oct. 31, 1972 to G. E. Smith; and U.S. Pat. No. 3,461,584, issued Aug. 19, 1969 to M. E. Wilson. In the Marecek patent, there is disclosed a removable tailgate sign for use on a vehicle tailgate of, for example, a pickup truck. The sign wraps around the tailgate and can be secured using any of a number of different fastening arrangements. The Smith patent discloses a temporary vehicle marking that is designed to attach on top of the hood, roof, or trunk of an automobile. The sign is attached using straps and clips, with the clips being attachable over the edges of a vehicle body panel and the straps being adjustable so that they may be tensioned to tightly retain the vehicle marker in place. The Wilson patent discloses a sign holder that attaches over a vehicle door and that is otherwise similar to the vehicle marker disclosed by Smith.
While suitable for their intended purpose, the signage systems disclosed in these patents are not suitable for transportable storage tanks for a number of reasons. First, such tanks do not have individual body panels to which the above-noted signage systems can be attached. Rather, they typically include only an upper lifting lug and a pair of lower feet at each end of the tanks. Secondly, as mentioned above, current government regulations typically require placarding at each side and each end of the storage tank. To address these unique requirements, individual magnetic placards have sometimes been utilized. These placards include a flexible magnetic substrate with a suitable warning or other marking indicia printed thereon. The placards are then simply attached to the storage tanks at the appropriate locations and are retained in place by the magnetic attraction of the substrate to the metal storage tank wall. However, these placards have been found to detach at higher speeds, thereby defeating their purpose and exposing the carrier to the risk of substantial fines.
Accordingly, there exists a need for a placard system that can be removably attached to a storage tank which overcomes the above-noted disadvantages of currently existing arrangements.